This proposal describes plans for the continuation of a comprehensive research program involving synthesis, mechanistic/mode of action, biological, and computer modeling studies directed at understanding the molecular basis of tumor promotion (a human health problem), the regulation and biochemistry of protein kinase C (a novel target for new drug development), the rational design of cancer chemotherapeutic agents based on protein kinase C, and more generally of molecules of interest in cancer and medicinal research. Five projects are proposed for investigation. A major continuation study will be directed at the synthesis of phorbol and ingenol analogues, the most potent tumor promoters known, and at an investigation of the structural basis for their tumor promoting activity. A second major project is directed at the synthesis and biochemical mode of action of resiniferatoxin, one of the most potent irritants known, an exciting probe for the study of neuronal receptors, and a lead for the development of new drugs for relief of neuralgic pain. A third major study involves efforts directed at the synthesis and biochemical mode of action of calphostin, a new, light-activatable phorbol ester antagonist and a potential lead for the development of new anti-AIDS drugs. A fourth major project is focussed on cyclic diacyl glycerols (cDAGs), a new family of potent PKC activators, on the synthesis of new metabolically stable cDAG analogues, and on the investigation of how lipid structure in these and other molecules functioning at lipid bilayers affects the affinity and selectivity of PKC isozyme recognition. A final major project seeks to define the tertiary structure of the regulatory domain of PKC through the use of photoaffinity labeling, synthesis, computer modeling, and NMR studies. Overall, this research program is expected to be of significant value in chemistry, biology, and medicine.